The present invention relates to a latching mechanism for securing a door and particularly to a door latching mechanism which includes a lock chassis designed to move a latchbolt between an extended and a retracted position.
Conventional door latching mechanisms include a lock chassis which moves a latchbolt between an extended position and a retracted position. In the extended position, the latchbolt engages a hole in the door frame and the door cannot freely open. With the latchbolt retracted, the door can be freely opened.
A typical lock chassis includes a spindle that interacts with a slide. The slide is typically slidably positioned between a chassis frame and a chassis flange coupled to the chassis frame. Rotation of the spindle translates into linear motion of the slide through a camming action. The slide engages the latchbolt and xe2x80x9cpullsxe2x80x9d the latchbolt out of its extended position and into its retracted position. The spindle of a typical lock chassis is coupled to a door handle or lever and is rotated when a user turns the door handle. Thus, turning the door handle draws the latchbolt out of its extended position and into its retracted position, allowing the door to be opened. Further, a typical lock chassis includes a cover, which surrounds and contains the chassis frame, the slide, and the flange.
Given the structure described above, a lateral blow to the door handle is translated through the lock chassis via the spindle. Because of this, such a blow to the door handle can cause the chassis frame to separate from both the chassis flange and the cover inside the door. In this way, access to the lock chassis can be gained from the outside of the door and the latchbolt can be retracted, thus allowing the door to be opened by an unauthorized user.
For a door latching mechanism to achieve a particular rating, industry regulations dictate that the lock chassis withstand certain lateral forces applied to the door handle. Therefore, a device that is readily installable on a lock chassis and which enables a lock chassis to withstand certain lateral forces would be welcomed by users of such a lock chassis.
According to the present invention, a lock chassis includes an insert having two wings positioned on opposite sides of a slide of the lock chassis from each other and at least a portion of each wing is positioned to lie between the slide and an interior surface of a cover, which houses the slide.
In preferred embodiments, the insert is positioned around a spindle and a hub of the lock chassis and the two wings flank a chassis frame housed within the cover. The frame is coupled to a flange and houses the slide, which is adapted to move linearly with respect to the frame. In preferred embodiments, the insert is made of zinc and its wings consume a substantial portion of a void which exists between an exterior surface of the frame and the interior surface of the cover.
Additional features and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived.